/*
 * Copyright 2010-2016 OrientDB LTD (http://orientdb.com)
 * Copyright 2013 Geomatys.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.orientechnologies.orient.core.sql.method.misc;

import com.orientechnologies.common.collection.OMultiValue;
import com.orientechnologies.common.log.OLogManager;
import com.orientechnologies.common.log.OLogger;
import com.orientechnologies.orient.core.command.OCommandContext;
import com.orientechnologies.orient.core.db.record.OIdentifiable;
import com.orientechnologies.orient.core.id.ORecordId;
import com.orientechnologies.orient.core.record.ORecord;
import com.orientechnologies.orient.core.record.impl.ODocument;
import com.orientechnologies.orient.core.record.impl.ODocumentHelper;
import com.orientechnologies.orient.core.sql.executor.OResult;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * @author Johann Sorel (Geomatys)
 * @author Luca Garulli (l.garulli--(at)--orientdb.com)
 */
public class OSQLMethodField extends OAbstractSQLMethod {
  private static final OLogger logger = OLogManager.instance().logger(OSQLMethodField.class);

  public static final String NAME = "field";

  public OSQLMethodField() {
    super(NAME, 1, 1);
  }

  @Override
  public Object execute(
      Object iThis,
      final OIdentifiable iCurrentRecord,
      final OCommandContext iContext,
      Object ioResult,
      final Object[] iParams) {
    if (iParams[0] == null) return null;

    final String paramAsString = iParams[0].toString();

    if (ioResult != null) {
      if (ioResult instanceof OResult) {
        ioResult = ((OResult) ioResult).toElement();
      }
      if (ioResult instanceof Iterable && !(ioResult instanceof ODocument)) {
        ioResult = ((Iterable) ioResult).iterator();
      }
      if (ioResult instanceof String) {
        try {
          ORecordId id = new ORecordId((String) ioResult);
          ioResult = iContext.getDatabase().load(id);
          if (ioResult == null) {
            ioResult = new ODocument(id);
          }
        } catch (Exception e) {
          logger.error("Error on reading rid with value '%s'", e, ioResult);
          ioResult = null;
        }
      } else if (ioResult instanceof ORecord) {
        // Do nothing
      } else if (ioResult instanceof OIdentifiable) {
        ioResult = iContext.getDatabase().load(((OIdentifiable) ioResult).getIdentity());
      } else if (ioResult instanceof Collection<?>
          || ioResult instanceof Iterator<?>
          || ioResult.getClass().isArray()) {
        final List<Object> result = new ArrayList<Object>(OMultiValue.getSize(ioResult));
        for (Object o : OMultiValue.getMultiValueIterable(ioResult, false)) {
          Object newlyAdded = ODocumentHelper.getFieldValue(o, paramAsString);
          if (OMultiValue.isMultiValue(newlyAdded)) {
            if (newlyAdded instanceof Map || newlyAdded instanceof OIdentifiable) {
              result.add(newlyAdded);
            } else
              for (Object item : OMultiValue.getMultiValueIterable(newlyAdded)) {
                result.add(item);
              }
          } else {
            result.add(newlyAdded);
          }
        }
        return result;
      }
    }

    if (!"*".equals(paramAsString) && ioResult != null) {
      if (ioResult instanceof OCommandContext) {
        ioResult = ((OCommandContext) ioResult).getVariable(paramAsString);
      } else {
        ioResult = ODocumentHelper.getFieldValue(ioResult, paramAsString, iContext);
      }
    }

    return ioResult;
  }
}
